正则表达式是特别常用的数据提取工具,功能组合非常强大,下面是ios下的正则表达是介绍,除了转义字符的处理上不同,其它方面与普通的正则表达是语法相同。
一、什么是正则表达式
正则表达式可以检测给定的字符串是否符合我们定义的逻辑,也可以从字符串中获取我们想要的特定部分。
二、正则表达式的语法
看一个过滤纯数字的例子
- (BOOL)validateNumber:(NSString *) textString
{
NSString* number=@"^[0-9]+$";
NSPredicate *numberPre = [NSPredicate predicateWithFormat:@"SELF MATCHES ...
.
Any character except newline.
.
A period (and so on for *, (, , etc.)
^
The start of the string.
$
The end of the string.
d,w,s
A digit, word
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